References to various vitamin D derivatives are extant in the patent and other literature. See, for example, U.S. Pat. Nos.: 3,565,924 directed to 25-hydroxycholecalciferol; 3,697,559 directed to 1,25-dihydroxycholecalciferol; U.S. Pat. No. 3,741,996 directed to 1.alpha.-hydroxycholecalciferol; U.S. Pat. No. 3,907,843 directed to 1.alpha.-hydroxygocalciferol; U.S. Pat. No. 3,715,374 directed to 24,25-dihydroxycholecalciferol; U.S. Pat. No. 3,739,001 directed to 25,26-dihydroxycholecalciferol; U.S. Pat. No. 3,786,062 directed to 22-dehydro-25-hydroxycholecalciferol; U.S. Pat. No. 3,847,955 directed to 1,24,25-trihydroxycholecalciferol; U.S. Pat. No. 3,906,014 directed to 3-deoxy-1.alpha.-hydroxycholecalciferol; U.S. Pat. No. 4,069,321 directed to the preparation of various side chain fluorinated vitamin D.sub.3 derivatives and side chain fluorinated dihydrotrachysterol.sub.3 analogs.
Although earlier studies have reported vitamin D.sub.3 -like metabolites in bile more polar than 25-hydroxy vitamin D.sub.3 or 1,25(OH).sub.2 D.sub.3, none of such metabolites has been positively identified (see Avioli et al, J. Clin. Invest. 46, 983-992 (1967); Bell et al, Biochem. J. 115, 663-669 (1969); Imrie et al, Arch. Biochem. Biophys. 120, 525-532 (1967). Bell et al report that the major metabolite of vitamin D found in rat bile appears to be a glucuronide conjugate not identical with synthetic cholecalciferyl glucuronide.